Department of Anthropology, University of Toronto Mississauga, Mississauga, ON, L5L 1C6, Canada.
Human Evolution Research Institute, University of Cape Town, Rondebosch, 7701, South Africa.
Sci Rep. 2022 Jul 22;12(1):12516. doi: 10.1038/s41598-022-16734-x.
Afro-Eurasian monkeys originated in the Miocene and are the most species-rich modern primate family. Molecular and fossil data have provided considerable insight into their evolutionary divergence, but we know considerably less about the evolutionary processes that underlie these differences. Here, we apply tests developed from quantitative genetics theory to a large (n > 3000) cranio-mandibular morphometric dataset, investigating the relative importance of adaptation (natural selection) and neutral processes (genetic drift) in shaping diversity at different taxonomic levels, an approach applied previously to monkeys of the Americas, apes, hominins, and other vertebrate taxa. Results indicate that natural selection, particularly for differences in size, plays a significant role in diversifying Afro-Eurasian monkeys as a whole. However, drift appears to better explain skull divergence within the subfamily Colobinae, and in particular the African colobine clade, likely due to habitat fragmentation. Small and declining population sizes make it likely that drift will continue in this taxon, with potentially dire implications for genetic diversity and future resilience in the face of environmental change. For the other taxa, many of whom also have decreasing populations and are threatened, understanding adaptive pressures similarly helps identify relative vulnerability and may assist with prioritising scarce conservation resources.
非欧亚类人猿起源于中新世，是现代灵长类动物中物种最丰富的家族。分子和化石数据为它们的进化分歧提供了相当多的见解，但我们对构成这些差异的进化过程知之甚少。在这里，我们应用从数量遗传学理论中发展出来的测试方法，对一个大型（n>3000）的颅颌形态计量学数据集进行了研究，调查了适应（自然选择）和中性过程（遗传漂变）在不同分类水平上塑造多样性的相对重要性，这种方法以前曾应用于美洲猴、猿、人类和其他脊椎动物类群。结果表明，自然选择，特别是对大小差异的自然选择，在整个非欧亚类人猿的多样化中起着重要作用。然而，漂移似乎更能解释科洛布inae 亚科内部的颅骨分歧，特别是非洲科洛布支系，这可能是由于栖息地的破碎化。小而不断减少的种群规模使得漂移很可能在这个分类单元中继续下去，这可能对遗传多样性和未来面对环境变化的恢复力产生严重影响。对于其他分类单元，其中许多分类单元的种群也在减少并受到威胁，了解适应性压力同样有助于确定相对脆弱性，并可能有助于优先利用稀缺的保护资源。
